METHOD FOR PRODUCING POLYHYDROXYALKANOATE (PHAs) USING HALOBACTERIUM AND HALOBACTERIUM

a technology of halobacterium and polyhydroxyalkanoate, which is applied in the direction of microorganisms, bacteria-based processes, biofuels, etc., can solve the problems of inferior performance and once more high price of biodegradable plastics, and achieve the effect of high salt concentration

Active Publication Date: 2011-05-05
NAT INST OF ADVANCED IND SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0014]According to the PHA production method of the present invention using a halobacterium, PHAs can be accumulated by one-step incubation in an environment wherein contamination by other bacteria is less likely to occur, without using expensive organic carbon and nitrogen sources, such as peptone and yeast extract, as conventionally used in the production of PHAs. In the present invention, it is not necessary for the growth of the halobacterium to use a medium containing several organic carbon and nitrogen sources, such as peptone and yeast extract; therefore for example, the halobacterium can be used in the treatment of BDF waste containing glycerol etc. and having a high salt concentration, and can be co-cultured with Spirulina, which is photosynthetic microalgae, and the like.
[0015]Moreover, when sugar etc. are used as a substrate, a homopolymer of hydroxybutyrate is formed; and when n-propanol or propionic acid is used as an organic carbon source for culture, a copolymer containing not only hydroxybutyrate, but also hydroxyvalerate in an amount of up to 13%, as constituent components can be prepared.
[0016]In the production of biodiesel fuel (BDF), which is increasingly used as environment-friendly fuel, the mainstream method is to produce fatty acid methyl ester (the main body of BDF) from vegetable and animal fat and oil using alkaline catalysts, such as potassium hydroxide and sodium hydroxide. This technique poses a problem in the treatment of waste glycerol that contains a large amount of alkali. However, after removing methanol, such waste glycerol can be used as a carbon source by the halobacterium to produce PHAs.
[0017]Furthermore, the halobacterium will presumably be effective in the production of PHAs during wastewater treatment in which insoluble organic substances are removed by filtration etc. from alkaline waste liquid (pickle waste liquid etc.) that contains a high concentration of salt.

Problems solved by technology

Compared to general persistent plastics, biodegradable plastics were once more expensive and inferior in performance; however, biodegradable plastics overcame such drawbacks and are now being used in practical application.

Method used

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  • METHOD FOR PRODUCING POLYHYDROXYALKANOATE (PHAs) USING HALOBACTERIUM AND HALOBACTERIUM
  • METHOD FOR PRODUCING POLYHYDROXYALKANOATE (PHAs) USING HALOBACTERIUM AND HALOBACTERIUM
  • METHOD FOR PRODUCING POLYHYDROXYALKANOATE (PHAs) USING HALOBACTERIUM AND HALOBACTERIUM

Examples

Experimental program
Comparison scheme
Effect test

examples

[0060]The present invention is described in detail below with reference to Examples.

[0061]The Examples illustrate a method of producing polyhydroxyalkanoates (PHAs), which are biodegradable aliphatic-polyester plastics produced by microorganisms.

Medium Composition

[0062]The media used were SOT media (available from the National Institute for Environmental Studies) to which each carbon source had been added.

Medium name: modified SOT (modified Spirulina platensis medium)

Medium constituents:

NaHCO31.68gK2HPO450mgNaNO3250mgK2SO4100mgNaCl100mgMgSO4•7H2O20mgCaCl2•2H2O4mgFeSO4•7H2O1mgNa2 EDTA8mgA5 + Co solution0.1ml

For example, 1.0 g of sodium acetate is used as a carbon source. All of the constituents are dissolved in distilled water, and the total amount is adjusted to 100 ml.

A5 + Co solution (modified)H3BO3286mgMnSO4•7H2O250mgZnSO4•7H2O22.2mgCuSO4•5H2O7.9mgNa2MoO4•2H2O2.1mgCo(NO3)6H2O4.398mgDistilled water100ml

In sterilization, the above medium constituents are divided into two groups:

SOT...

example 2

Culture of Halomonas sp. KM-1 Strain in Different pH Environments

[0080]The halophilic-bacterium Halomonas sp. KM-1 strain was cultured in different pH environments using glycerol 3 w / v % as a carbon source, and the PHB ratio (PHAs / dry cell) accumulated in the cells was measured. To the SOT-A (NaHCO3: 1.68 g (0.2 M), K2HPO4: 50 mg / 50 ml) double-concentrated aqueous solution, which was a buffer component, a SOT-A′ (Na2CO3: 2.12 g, K2HPO4: 50 mg / 50 ml) double-concentrated aqueous solution was added, and solutions at pH 10 and pH 10.5 were prepared using a pH meter. Each solution was mixed with the same amount of SOT-B double-concentrated solution, and used as a medium. The PHB ratio of each medium was relativized with respect to the culture time, and plotted in FIG. 5.

[0081]The Halomonas sp. KM-1 strain showed a PHA accumulation rate equal to or more than that at pH 8.9 not only under the normal culture conditions (pH 8.9), but also at pHs 10 and 10.5. Further, the possibility of the u...

example 3

[0082]Table 2 shows the typical compositions of waste glycerol formed as a by-product in the production of biodiesel, which has great potential as an organic carbon source.

TABLE 2Analysis results of waste glycerolpHGlycerol (mg / g)K (mg / g)Waste glycerol #110.3035041.8Waste glycerol #210.3840062.1Waste glycerol #310.3535845.9Waste glycerol #410.3735846.0* pH: those measured in samples prepared by dissolving 1 g of waste glycerol in distilled water (total amount: 100 ml) (adapted from Journal of Environmental Conservation Engineering, Vol. 37, No. 5, pp. 48-53)

[0083]In general biodiesel production equipment, KOH having a high solubility in methanol is used as an alkaline catalyst.

[0084]The waste glycerol actually used for culture was a waste glycerol sample that was kindly provided by the Kyoto Municipal Waste Edible Oil Fuel Production Facility on May 1, 2008.

[0085]The pH of this sample was measured in the same manner as described above, and the result was 10.38.

[0086]Then, media comp...

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Abstract

Disclosed are a method for producing polyhydroxyalkanoates (PHAs) using a halobacterium belonging to the genus Halomonas, wherein the halobacterium can grow in a medium consisting of an inorganic salt and a single organic carbon source and having a pH of 8.8 to 11, and produce PHAs in an amount of 20 wt. % or more based on the dry cell weight, and the halobacterium is cultured in an alkaline medium containing an inorganic salt and one or more organic carbon sources to produce PHAs in an amount of 20 wt. % or more based on the dry cell weight; and the halobacterium belonging to the genus Halomonas, which can grow in a medium consisting an inorganic salt and a single organic carbon source and having a pH of 8.8 to 11, and produce PHAs in an amount of 20 wt. % or more based on the dry cell weight.

Description

TECHNICAL FIELD[0001]The present invention relates to a method for producing biodegradable plastics, i.e., polyhydroxyalkanoates (PHAs), using a halobacterium, and relates to the halobacterium belonging to the genus Halomonas. BACKGROUND ART[0002]Biodegradable plastics have attracted attention from the standpoint of the prevention of environmental destruction, because they are decomposed by the action of microorganisms and the like in, for example, soil. Compared to general persistent plastics, biodegradable plastics were once more expensive and inferior in performance; however, biodegradable plastics overcame such drawbacks and are now being used in practical application. Demand has increased for mass production technologies for biodegradable plastics along with an increase in the usage of biodegradable plastics.[0003]Polyhydroxyalkanoates, which are a type of biodegradable plastic, are produced by a wide range of bacteria, such as hydrogen bacteria (Ralstonia), cyanobacteria, and ...

Claims

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Application Information

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IPC IPC(8): C12P7/62C12N1/20
CPCC12R1/01C12P2201/00C12P7/625Y02E50/13Y02E50/10C12R2001/01C12N1/205
Inventor KAWATA, YOSHIKAZUAIBA, SEIICHI
Owner NAT INST OF ADVANCED IND SCI & TECH
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